A more fascinating version of what David said is when the computer uses an algorithm and uses it to make the 0's and 1's less, so it's smaller. It also checks out how strong the computer is (benchmark) before getting the new work unit.
Oh, alright, mine isn't more fascinating, it's just me being me. OH LOOK! A DISTRACTION!!! *Runs off to do something*

WCGrid_Rosetta.exe writes an encrypted fold prediction to a temporary work file while it is running. This work file tells the program where it should start whenever the computer is rebooted. This allows people to shut down their computer without losing all their calculations. When the last fold prediction is made, Rosetta reads and decrypts the file. Then it compresses the data into a much shorter results file and encrypts it. Then it contacts the server, sends back the results, and downloads the next work unit, plus points awarded and any changes to the profile or update to the software.

Thankyou very much everyone. Amaizing how much knowledge is available - all you have to do is ask!!

Thank you.